http://articles.moneycentral.msn.com/CollegeAndFamily/LoveAndMoney/GetRealMarriageIsABusiness.aspx
The median net worth of married-couple households in the latest Census Bureau wealth study, conducted in 2002, was $101,975. For single men, median wealth was $23,700. For single women, $20,217.
* A 15-year study of 9,000 people found that during that time, people who married and stayed married built up nearly twice the net worth of people who stayed single. Even when all other factors are held constant -- stuff like income and education -- just the fact that they were married contributed to a 4% annual rise in these couples' wealth.
* Wealth declines typically started four years before a divorce was final, and the breakup ultimately reduced the typical person's net worth by 77% of that of the average single person.